1. Field of the Invention
The present invention relates to a sub-mount and to a light transmission and reception module, more specifically, to a sub-mount mounted in a package of an optical device and to a light transmission and reception module using the same.
2. Description of the Related Art
Recently, in IC technique or LSI technique, optical wiring between equipments, between boards in the equipments, or in a chip is given attention instead of the electrical wiring at high density to enhance the operating speed or integration degree.
In Japanese Patent Application Laid-Open No. 2000-39530, for example, an optical element including a light emitting element and a light detecting element in a core clad stacking direction of a polymer optical waveguide including the core and the clad surrounding the core, and further including an incident side mirror where light emitted from the light emitting element is coupled and a emission side mirror emitting the light to the light detecting element. In the publication, the optical element is disclosed in which the clad layer is formed into a concave shape at locations corresponding to the light paths from the light emitting element to the incident side mirror, and from the emission side mirror to the light detecting element, at where the light from the light emitting element and the light from the emission side mirror converge.
Further, in Japanese Patent Application Laid-Open No. 2000-39531, an optical element is disclosed in which light from a light emitting element is coupled at a core end surface of a polymer optical waveguide including the core and a clad surrounding the core. In the optical element, the end surface of the core is formed into a convex surface towards the light emitting element so that the light from the light emitting element is converged and a wave loss is suppressed.
Further, in Japanese Patent Application Laid-Open No. 2000-235127, an optoelectronic integrated circuit is disclosed in which the polymer optical waveguide circuit is directly assembled on the circuit integrating the electronic elements and optical elements.
When the above elements are packaged in an optical wiring and can be incorporated into a device, the assembling flexibility of the optical wiring can be increased. As a result, a light transmission and reception element with compact shape can be manufactured.
However, the methods proposed so far requires a mirror to be embedded to form a 90° return mirror, and requires positioning at high precision when laminating the waveguide and the light transmission and reception element, and thus the cost required for mounting becomes large.
A polymer optical waveguide module equipped with light emitting and detecting elements including a polymer optical waveguide film was disclosed by the present inventors (Japanese Patent Application No. 2004-139041, Japanese Patent Application FE04-04966). In the disclosure, the polymer optical waveguide film includes a light path conversion mirror surface and an abutting surface on the same end.
A semiconductor laser device in which a mirror surface is formed on a sub-mount of a semiconductor laser, wherein a light path of the laser light is converted by such mirror surface is disclosed in Japanese Patent Application Laid-Open No. 2000-114655.
However, when mounting a light emitting element or a light detecting element and a waveguide element in the sub-mount, an adhesive must be applied to a predetermined position at excellent precision in case that the adhesive (including electrically conductive paste) is used for fixation. Further, the adhesive may flow out from a recess for mounting when the element is mounted.
The present invention provides a sub-mount for mounting an optical component in which the adhesive is applied to a predetermined position at excellent precision and is prevented from flowing out, and in which the optical component is easily and reliably mounted; and a light transmission and reception module using the same.